This invention relates to improved roofing structures and methods. Various types of molded roofing tiles or shingles have been proposed in the past, formed of numerous different materials intended to attain improved structural characteristics in a roof. For example, U.S. Pat. No. 848,537 issued Mar. 26, 1907 to C. C. Davis on "Reinforced Tile Or Slab" shows a roofing tile formed of concrete containing corrugated expanded metal mesh embedded within the concrete and reinforcing it. The tiles of this patent are secured in place by lugs projecting downwardly from the tiles and adapted to be secured by bolts to angle irons attached to the rocf support structure. U.S. Pat. No. 2,142,305 issued Jan. 3, 1939 to C. F. Davis on "Building Unit And Construction" shows a number of different types of building slabs or units molded of cementitious material and having metal edge members and/or internal reinforcing sheets. Others types of shingles or tiles are shown in U.S. Pat. Nos. 912,057, 2,644,410, 881,522, 1,093,761, 4,262,466 and 1,150,425.